mongo查询抛出的这个异常，各位大侠知道是啥原因吗

Question

软件版本：python2.7，pymongo3.2 ,MongoDB3.2

错误信息:在用find_one方法查询时 data=db.find_one({'cid':tempDict['cid']}) ，抛出如下错, 查了好久也没查出原因。。。

File "build/bdist.linux-x86_64/egg/pymongo/collection.py", line 1006, in find_one
    for result in cursor.limit(-1):
  File "build/bdist.linux-x86_64/egg/pymongo/cursor.py", line 1097, in next
    if len(self.__data) or self._refresh():
  File "build/bdist.linux-x86_64/egg/pymongo/cursor.py", line 1019, in _refresh
    self.__read_concern))
  File "build/bdist.linux-x86_64/egg/pymongo/cursor.py", line 905, in __send_message
    helpers._check_command_response(doc['data'][0])
  File "build/bdist.linux-x86_64/egg/pymongo/helpers.py", line 196, in _check_command_response
    raise OperationFailure(msg % errmsg, code, response)
OperationFailure: could not find host matching read preference { mode: "primary", tags: [ {} ] } for set rs1

Answer 1

非常感谢Karblue，你的答复总算让我找到点头绪

Answer 2

但不知道如何下手，我们的mongo是两台分片，难道并发量大，就出现连不上的情况，目前这种错只是偶尔出现

Answer 3

回复
看看网络原因呢。表象上就是无法连上primary服务器了。为什么连不上原因就太多了。。

Answer 4

primary

All read operations use only the current replica set primary. [5] This is the default read mode. If the primary is unavailable, read operations produce an error or throw an exception.

看样子的确是这样. primary 服务器不可用。 read操作就会抛出异常。

详情见：https://docs.mongodb.org/manual/reference/read-preference/

Answer 5

貌似是无法连接mongodb 的primary主服务器。

Answer 6

Answer 7

自己顶下